/* =========================================================
 * BUYU 全量样式表（深色玻璃拟态 + 白色精致主题 + 大按钮）
 * 版本：fix-20251031
 * =======================================================*/
:root {
  --bg: #0b1020;
  --card: rgba(255,255,255,0.08);
  --card-border: rgba(255,255,255,0.12);
  --text: #e7ecf4;
  --muted: #a6b0c3;
  --accent: #6ea8fe;
  --accent-2: #9b8cff;
  --good: #22c55e; --bad:#ef4444;
}
*{box-sizing:border-box} html,body{height:100%}
body{
  margin:0;
  background: radial-gradient(1200px 600px at 20% -10%, #1b2350, transparent 60%),
              radial-gradient(1000px 500px at 120% 0%, #351b5e, transparent 60%),
              var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased; -moz-osx-font-smoothing:grayscale;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, "Noto Sans";
}
.container{max-width:960px;margin:0 auto;padding:20px}
a{color:var(--accent);text-decoration:none} a:hover{opacity:.9}
.muted{color:var(--muted)} h1,h2,h3{margin:0 0 14px}

/* 深色旧页组件 */
.card{background:var(--card);border:1px solid var(--card-border);backdrop-filter:blur(12px);border-radius:20px;padding:28px;box-shadow:0 10px 40px rgba(0,0,0,.25)}
.nav{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}
.input{width:100%;background:rgba(255,255,255,.06);border:1px solid var(--card-border);border-radius:12px;color:var(--text);padding:14px 16px;margin-top:10px;outline:none;transition:border .2s, box-shadow .2s}
.input:focus{border-color:var(--accent);box-shadow:0 0 0 4px rgba(110,168,254,.15)}
.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 18px;border-radius:12px;border:1px solid transparent;color:#fff;cursor:pointer;background:linear-gradient(135deg, var(--accent), var(--accent-2));font-weight:600;transition:transform .05s, box-shadow .2s, filter .2s}
.button:hover{box-shadow:0 6px 22px rgba(110,168,254,.35)} .button:active{transform:translateY(1px)}
.badge{font-size:12px;color:var(--muted)}
.q-title{font-weight:700;margin:10px 0}
.options{display:flex;flex-direction:column;gap:10px}
.opt{padding:12px 14px;border:1px solid var(--card-border);border-radius:12px;background:rgba(255,255,255,.04);cursor:pointer;display:flex;align-items:center;gap:12px;transition:border-color .2s, box-shadow .2s, background .2s}
.opt:hover{border-color:var(--accent);box-shadow:0 3px 14px rgba(0,0,0,.18)}
.opt input{transform:scale(1.1)}
.opt.correct{border-color:var(--good)} .opt.wrong{border-color:var(--bad)}
.explain{margin-top:12px;padding:12px 14px;border-left:3px solid var(--accent);background:rgba(255,255,255,.04);border-radius:8px}
.controls{display:flex;gap:12px;margin-top:16px;flex-wrap:wrap}
.progress{height:10px;background:rgba(255,255,255,.08);border:1px solid var(--card-border);border-radius:999px;overflow:hidden;margin:8px 0 0}
.bar{height:100%;width:0%;background:linear-gradient(90deg, var(--accent), var(--accent-2));transition:width .25s}
.footer{color:var(--muted);font-size:12px;text-align:center;margin-top:28px}
@media (max-width:560px){.container{padding:16px}}

/* 白色精致主题（quiz/review 专用） */
.theme-clean{background:#f7f8fb;color:#111827;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,PingFang SC,Hiragino Sans GB,Microsoft YaHei,Helvetica Neue,Arial,Noto Sans}
.theme-clean .nav-clean{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
.theme-clean .nav-clean .left{display:flex;align-items:center;gap:8px;font-weight:700}
.theme-clean .nav-clean .sep{color:#c0c8d8}
.theme-clean .nav-clean .right{display:flex;align-items:center;gap:12px}
.theme-clean .nav-clean .link{color:#4b5565;text-decoration:none}
.theme-clean .nav-clean .link:hover{color:#111}
.theme-clean .card-clean{background:#fff;border:1px solid #e6e9f2;border-radius:16px;box-shadow:0 6px 20px rgba(17,24,39,.06);padding:16px}
.theme-clean .toolbar{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px;gap:12px}
.theme-clean .badge.clean{background:#eef2ff;color:#3b5bfd;border:1px solid #d9e0ff;border-radius:999px;padding:4px 10px;font-size:12px}
.theme-clean .sel{height:36px;border:1px solid #e3e7ef;border-radius:10px;background:#fff;color:#111;padding:0 10px;outline:none}
.theme-clean .sel:focus{border-color:#c7ccd4}

.theme-clean .btn{display:inline-flex;align-items:center;justify-content:center;height:44px;min-width:120px;padding:0 22px;border-radius:12px;cursor:pointer;font-size:15px;font-weight:600;background:#fff;color:#1f2937;border:1px solid #d1d5db;box-shadow:0 2px 6px rgba(0,0,0,.04);transition:all .2s}
.theme-clean .btn:hover{background:#f3f4f6;border-color:#c7ccd4;box-shadow:0 3px 10px rgba(0,0,0,.08)}
.theme-clean .btn:active{transform:translateY(1px);box-shadow:0 1px 4px rgba(0,0,0,.1)}
.theme-clean .btn.primary{background:linear-gradient(90deg,#2563eb,#1d4ed8);border-color:#1d4ed8;color:#fff;box-shadow:0 3px 12px rgba(29,78,216,.25)}
.theme-clean .btn.primary:hover{background:linear-gradient(90deg,#1e40af,#1d4ed8);box-shadow:0 4px 14px rgba(29,78,216,.3)}
.theme-clean .btn.ghost{background:#fff;border:1px solid #d1d5db;color:#374151}
.theme-clean .btn.ghost:hover{background:#f9fafb;border-color:#9ca3af}

.theme-clean .kbd{font-size:12px;color:#64748b;background:#f1f5f9;border:1px solid #e2e8f0;padding:2px 6px;border-radius:6px}
.theme-clean .muted{color:#7a8599}
.theme-clean .muted-box{color:#4b5565;background:#f1f3f8;border:1px solid #e6e9f2;border-radius:10px;padding:12px 14px}

.theme-clean .q-box{padding:18px 18px 16px}
.theme-clean .q-head{display:flex;align-items:center;justify-content:space-between;gap:12px}
.theme-clean .q-meta .badge.idx{color:#59607a;font-size:13px}
.theme-clean .q-progress{flex:1}
.theme-clean .progress{height:8px;width:100%;background:#f1f3f8;border:1px solid #e6e9f2;border-radius:999px;overflow:hidden}
.theme-clean .bar{height:100%;width:0%;background:linear-gradient(90deg,#5b7cfa 0%,#7a5bfa 100%);transition:width .25s}
.theme-clean .q-title{font-weight:700;font-size:18px;margin:10px 0 4px}
.theme-clean .options{display:flex;flex-direction:column;gap:12px}
.theme-clean .opt{display:flex;align-items:center;gap:12px;padding:12px 14px;border-radius:12px;cursor:pointer;border:1px solid #e9edf5;background:#fff;transition:border-color .2s, box-shadow .2s, background .2s}
.theme-clean .opt:hover{border-color:#cfd7ea;box-shadow:0 3px 10px rgba(31,41,55,.04)}
.theme-clean .opt.correct{border-color:#22c55e;background:#f0fff5}
.theme-clean .opt.wrong{border-color:#ef4444;background:#fff5f5}
.theme-clean .opt input{transform:scale(1.1)}
.theme-clean .controls{display:flex;justify-content:center;align-items:center;gap:16px;flex-wrap:wrap;margin-top:24px;padding-top:16px;border-top:1px solid #e9edf5}
.theme-clean .hint{display:block;width:100%;text-align:center;margin-top:6px;font-size:13px;color:#9ca3af}
.theme-clean .footer{text-align:center;margin-top:16px;font-size:12px;color:#7a8599}
@media (max-width:560px){.theme-clean .container{padding:16px}.theme-clean .q-title{font-size:16px}.theme-clean .btn{height:42px;min-width:110px;padding:0 18px}}